Q. A body projected vertically from the earth reaches a height equal to earth’s radius before returning to the earth. The power exerted by the gravitational force is greatest
A) At the instant just after the body is projected
B) At the highest position of the body
C) At the instant just before the body hits the earth
D) It remains constant all through
Explanation
(c) $P = \overrightarrow{F}.\overrightarrow{v} = Fv\cos\theta$
Just before hitting $\theta$ is zero and both $F,\ v$ are maximum
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.